With all those car exhausts, smog and fumes, you're right to be concerned about outdoor air pollution. But indoors, air quality isn't faring much better either. In fact, according to the U.S. Environmental Protection Agency (EPA), the air in most homes is 2 to 5 times more contaminated than the air outdoors, which can trigger allergies, respiratory diseases and other health problems.

But fortunately there are measures you can take to keep the air clear. Here are the top pollutants and what you can do if they're present in your home.

1. Volatile Organic Compound (VOCs)

Why it's bad: VOCs are emitted as gases by a wide range of household products like paint, cleaning products and pesticides which can be a hazard for indoor air quality. Studies have found levels of several of these organic pollutants to be 2 to 5 times higher inside homes than outside. If there isn't adequate ventilation in place, headaches, dizziness, fatigue, and nose, eye and throat irritation can all be triggered soon after coming into contact with VOCs.

How to tackle it: Buy products with low VOCs wherever you can. For household cleaning products, you may want to consider a more green alternative or even think about making your own natural cleaners (vinegar diluted with water, for example, can be used to wipe countertops). If you're planning to re-paint your walls, consider low-VOC paint and ventilate the area as far as possible. If you've got partially used cans of paint, the EPA advises seeing if there are any collections for toxic household waste planned in your area. If not, don't just deposit in the dustbin.

2. Mold

Why it's bad: Mold spores can become a problem if they come into contact with moisture. When molds start multiplying, they can produce allergens, irritants, and in some cases, potentially toxic substances (mycotoxins). Inhaling or touching mold or mold spores can trigger allergic reactions such as sneezing, a runny nose, red eyes as well as skin rash. For asthma sufferers, mold can also trigger asthma attacks.

How to tackle it: Make sure that you've got a good dehumidifier to control humidity, especially in the basement and attic. Mold can also be a big problem in the bathroom, with hot showers being a prominent culprit. Installing ventilation fans can go a long way towards helping with this. If any areas in your home are damaged by water, dry them out as quickly as possible after the event to limit the potential for mold to take hold.

3. Dust mites

Why it's bad: Your bedding is a potential haven for dust mites, which can trigger asthma attacks and allergies. Other likely homes for dust mites can include carpets, upholstery and stuffed toys.

How to tackle it: Wash bedding and stuffed toys at least once a week in hot water and let the vacuum cleaner loose on carpets and furniture frequently. Keep a check on humidity levels in the bedrooms. According to the EPA, you should be aiming for somewhere between 30% and 50% relative humidity.