Exhaust fumes cause acid air, pollution, cancer, lead-poisoning and a variety of bronchial and respiratory illnesses. The average car emits a cocktail of more than 1,000 pollutants:

- Tetra ethyl Lead: added to fuel to increase the output power of the engine is extremely toxic and can harm any organ of the body. Low level exposure over a long period commonly affects the nervous system and blood. Can impair the mental abilities of children. 7 out of 10 children in Mexico city have had their development stunted by lead poisoning from cars.    

- Benzene: occurs naturally in crude oil. High benzene crudes sometimes added to fuel to improve the properties of premium unleaded gasoline. Effects: a proven carcinogen. Studies on benzene-exposed workers show statistically significant association to acute leukemia.

- Carbon Monoxide: cars are the major source of carbon monoxide, accounting for over 65 percent of emissions in OECD countries. It affects human health by impairing the oxygen carrying capacity of the blood causing impaired perception, slowing reflexes and drowsiness. Increases occurrence of headaches and affects the central nervous system, the heart and the transference of blood around the body. In large doses, it is fatal.

- Nitrogen Dioxide: affects humans and plants, reducing growth and causing lesions in sensitive crops, whilst in humans causing irritation to the respiratory tract, reducing lung function and increasing susceptibility viral infections.

- Nitric Oxide and Nitrogen Dioxide: together play major role in formation of acid rain and in Europe are thought to contribute up to half of the acidification of rain. In OECD countries, 47 percent of nitrogen oxides come from road vehicles. They also contribute to the formation of ground level ozone, affect the acidification of soil and cause changes in ground flora—the development of nitrogen loving species at the expense of other species—and the over development of micro-flora in seas and lakes, creating a lack of oxygen in the water which kills wildlife.

- Low Level Ozone: The production of ozone is an indirect consequence of car pollution. It results from photochemical reactions between hydrocarbons and nitrogen oxides. Ozone is the main ingredient in photochemical smog, which effects eye irritation, headaches, coughing, impaired lung function and eye, nose and throat irritation. Asthmatics and children are most at risk. On a single bad day in Athens the smog can kill 8 people and send up to 200 people to hospital. Background levels of tropospheric ozone are thought to have doubled in the northern hemisphere over the past century. Ozone is also the single most important pollutant affecting vegetation. It damages food crops, particularly potatoes, tomatoes, wheat and spinach, with leaf diseases. This causes farmers to switch to less sensitive crops, leading to loss of biodiversity. With present ozone levels in Switzerland, agricultural losses cost at least US$200 per hectare. Ozone damage also affects forests in America and Europe—pines and larch are particularly sensitive.

- Sulfurous Emissions: cause soil and water acidification, damage to plants (especially trees, mosses and certain lichens), and smog.


Source: World Carfree Network, October, 2006. Available on: www.worldcarfree.net/resources/stats.php