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Survey and Health Assessment of Products for Interior Car Care

4 Description of the exposure scenarios

In the light of the survey results, relevant exposure scenarios were set up for the purchased car care products. The exposure scenarios have formed the basis of the preparation of the emission analyses and are used in connection with the exposure assessment in the health assessment.

The purchased car care products cover the following types of car care products:

  • Vinyl make-up – 9 spray products with propellant or pump and one single cream product
  • Glass cleaner – 5 spray products with propellant or pump and one single cream product
  • Fabric coating – 3 spray products with propellant or pump
  • Fabric cleaner – 9 spray products with propellant or pump
  • Odour remover – 2 spray products with propellant or pump
  • Vinyl cleaner – 3 spray products with propellant or pump
  • Leather cleaner – 2 spray products with propellant or pump
  • Cleaning tissue – 4 tissues
  • Anti-mist product – 1 spray product with pump and 1 tissue
  • Detergent - 1 foam spray with pump
  • Synthetic materials sealant – 1 cream product.

As it appears from the above list, most of the car care products for interior car care are spray products. The survey shows that three car care products are relevant in relation to an exposure assessment:

  • Spray products
  • Cream products
  • Tissues.

Table 4.1 gives an outline of the different application methods that are stated on the products. The table is organized according to the four different application methods found on the purchased products:

  • Sprayed on the surface to be treated. Wiped off with a cloth.
  • Sprayed directly on the cloth and spread on the surface.
  • Cream applied with a cloth.
  • Tissue is used.

In general, it applies to all car care products that separate directions for use are not supplied with the product. Only brief directions are written on the product itself. The directions for use on the different products mention the application possibilities that are listed in table 4.1. The four columns in the table represent four different application methods. For each of the four different application methods examples are given from the labels of the different products that were purchased.

Table 4.1 Examples of application methods. Each of the four columns represents the four different application methods described on the labels of the purchased products. The examples in the rows are examples of the application details written on the labels.
  The different application methods of products for interior car care
Examples from products Spray on the surface to be treated. Wipe off with a cloth. Spray directly on the cloth and spread on the surface. Cream applied with cloth. Use a tissue.
Example 1 A small amount is sprayed on the surface. Apply a thin layer with a cloth. Apply the product with a large cloth. Clean. The tissue is turned and folded as required.
Example 2 Spray in an even layer on the entire surface. Spray on the cloth and spread. Apply a very thin and even layer on the entire surface. If necessary, wipe off with a dry tissue.
Example 3 Only spray one thin layer on the surface. Apply with a cloth or sponge.    
Example 4 Spray at a distance of 5-10 cm.      
Example 5 Spray sparingly on the surface.      
Example 6 Spray a thin and even layer from a distance of app. 20-30 cm with circular movements.      
Example 7 Spray at a distance of app. 30 cm. If possible several times after intermediate drying.      
Example 8 Spray directly at a distance of 10-15 cm.      
Period of waiting Let it penetrate.
Let it work.
Let it work and dry.
Let it work for a short period.
Let it work 5-10 min.
Let it work 1-2 min.
Let it penetrate 30 seconds.
Let it work 2-3 min.
Let the item dry for some hours (fabric cleaner).
Let it work the night over with closed doors/windows (odour remover).		 Let it cure 45 min. (synthetic materials sealant)  

On the basis of the directions for use on the products there is in general no great difference between the application method in spite of the product differences (glass cleaner, vinyl cleaner and fabric guard). For instance, it is recommended to wipe off the fabric guard with a cloth after spraying in order to spread the product evenly. Still, it is expected that fabric guards and fabric cleaners are used rarely compared to the other types of car care products.

Information on how often the products are used is sparse. Some shops inform that car care often is a spring activity that especially is carried out by men. Therefore, some shops sell most products during spring. Other information indicates that some car owners drive to the local service station every week to wash, burnish and polish the car inside and outside.

4.1 Exposure scenarios

The situation that is analysed closer in this project is the following:

A car owner drives to the nearest service station for car detailing, i.e. to refuel, wash the car and polish it outside and inside. This project solely concentrates on polishing the inside of the car with products for interior car care.

It is anticipated that it takes app. 15 minutes per product to apply the product inside. During that time exposure can take place via inhalation as the products contain volatile compounds, but exposure can also take place via skin contact when the products are applied.

In connection with the calculations it is anticipated that it takes 15 minutes to apply each product. In the calculations, the exposure to several products is added up if for instance vinyl make-up as well as glass cleaner is used. Therefore, the worst-case situation is anticipated to be when both products are applied simultaneously, i.e. full exposure to both products at the same time. In practice that is not possible, but it is a necessary assumption in relation to the calculations.

Exposure to the substances is calculated per day, but it is anticipated that even the most energetic car care enthusiasts at a maximum polish and care for their cars once a week.

4.1.1 Skin contact

As mentioned, the survey shows that there are three types of car care products:

  • Spray products
  • Cream products
  • Tissues.

As previously mentioned, spray products can be products that are sprayed on the surface and afterwards have to be wiped off with a cloth. Cream products are applied with a cloth and tissues are used as they are.

In connection with spray products and cream products exposure via the skin is possible when the products are applied. Even if the person does not use gloves, the direct skin contact will be low as most of the car care product will be on the cloth. However, when using tissues, direct skin contact will occur.

It is anticipated that persons applying the product wash their hands immediately after application. All products are rather greasy and have a strong oily smell and therefore it is anticipated that there is a need to wash hands if the product gets on the fingers.

Of course, exposure will be higher if the person does not wash hands after application. However, exposure will still be minor as most of the products are applied with a cloth so the main part of the product does not come into contact with the skin.

4.1.2 Inhalation

Exposure via inhalation takes place during and after application, e.g. if the person stays in the car or goes for a drive in the car immediately after application.

This project deals with two inhalation scenarios:

  1. The product is applied (15 minutes) and then the person drives the car home from the local service station where application has taken place (15 minutes to drive home). That gives a total exposure of 30 minutes. Then there is no exposure (all substances are aired away before the car is used the next time).
  2. The product is applied (15 minutes) and then the person goes for a 5-hour drive in the car. 5 hours have been chosen because the emission tests showed that after that period of time most of the substances had been aired away and the concentrations declined substantially.

4.2 Selection of products for emission tests

A total of 4 emission test were carried out with the selected, purchased products for interior car care. The below types of products were chosen for the emission tests. These product types were selected because there is a wide range of them and they are believed to be the product types that are used most often.

  • Vinyl make-up (spray product)
  • Glass cleaner (spray product)
  • Fabric cleaner/fabric guard (spray product)
  • Vinyl cleaner (spray product).

In the light of the screening of compounds in the products, the products were selected that seemed to have the highest content of (health hazardous) volatile organic compounds.

4.3 Preparation of emission tests

The emission tests were prepared to represent a realistic worst-case situation. The relevant parameters chosen for the tests are described below and added up in Table 4.2.

The chemical structure and surface structure of a material are of importance to the evaporation of substances as some substances can be absorbed and in that way lower the evaporation speed. Therefore, realistic test samples were used for the emission tests. Examples are glass, fabric or plastic surfaces.

The size of the car cabin (as well as the temperature and air change) is of importance to the extent of exposure. Centre for Renewable Energy and Transport, Danish Technological Institute, gave the following information about the construction of a car: the volume of an average passenger car is app. 3.5 m³ while a van is somewhat bigger. The air temperature will often be between 20 and 23 ºC if there is air-conditioning, otherwise the temperature can become considerably higher locally. There is a construction requirement to the plastic parts around the windows, namely that they have to be able to be proof against temperatures over 60 ºC. In particular, there are often problems with the horizontal part of the dashboard and fabric at the rear windows. In several cars, reflecting material is used. Therefore, these plastic parts may have a somewhat higher temperature when protectants are applied.

The ventilation capacity varies a lot according to the type of car. It is estimated that the defroster fan in the most simple systems typically has a capacity of 3–5 m³ per minute. When driving with reduced fan speed the air change will by and large be the same due to the wind speed. When the fan is switched off, the air change will be speed dependent and can vary from almost 0 when the car is stopped and to almost the same level the fan can supply (i.e. once a minute) when the car is at full speed.

As initial scenario it is anticipated that a car owner drives to a service station to wash and polish his car and clean the car inside. It takes app. 15 minutes to polish/clean the car inside (per product). That is anticipated to be the concluding work and the car owner drives home from the service station immediately after (transport app. 15 min.), i.e. a 30 minute exposure during and after application. Another (worst-case) scenario is that the owner goes for a 5-hour drive in the car immediately after product application and therefore exposure time will be longer.

When using the product, the system will be partly open corresponding to the car door being open but without active air change (therefore air change is set to 0). Then the door is closed. It is anticipated that when driving in the car there is no active air change (the car doors/windows are closed and the ventilation is switched off). When driving in the car there will be a minor air change that will depend on the wind speed and the car speed, but to simulate the worst-case situation it is in these exposure scenarios anticipated that the car is almost completely closed (i.e. air change is set to 0).

Table 4.2 Emission tests
Description of the emission tests
Volume 0.42 m³ (cabin size: 420 L, Width 100 cm, Depth 60 cm, Height 70 cm).
Temperature Room temperature, app. 22 ºC.
Air change Almost 0 during application (it is anticipated that the car doors are open, but no fan is used).
Air change is set to 0 at all measurements to simulate a worst-case situation.
Amount of applied car care agent An amount is applied as estimated for simulated use.
Applied on The car care agent is applied on realistic test samples such as glass, fabric or plastic surfaces.
Sampling See result tables in section 5.2.2.
Stay in car in connection with application Time = 0-0.5 hours
15 minutes to apply the product. Then the cloth is removed from the car as it is anticipated that the person will throw the cloth away or remove it to be washed.
It is anticipated that it takes place at a service station and that the car is driven home immediately after (transport time app. 15 minutes), meaning that the total initial exposure is app. 30 minutes.
It is anticipated that the air change is zero (car almost tight and no ventilation).
Stay in car after application Time = 0.5 - 5 hours
As worst-case a 5-hour car drive after application is anticipated during which time exposure takes place. Therefore, exposure level measurements were carried out continuously for up to 5 hours after test start.

 

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Version 1.0 December 2010, © Danish Environmental Protection Agency