We all pollute the air, directly and indirectly. The choices we make at home, at work, and in transporting ourselves affect the air we breathe.
Most air pollution is invisible.
The exhaust from our cars, snowmobiles or lawnmowers drifts away and seemingly disappears. Emissions from most sources are cleaner in many ways than 30 years ago. But their collective impact is still a concern. Criteria pollutants The first air-quality issues the nation addressed were the obvious ones. Switching to unleaded gasoline largely eliminated lead in the air.