Particulates as atmospheric pollutants

Particulates are tiny solid particles or liquid droplets suspended in the air. When their amount in the air increases, they can affect both human health and the amount of sunlight reaching the ground.

Particulates and health

Small particulates can be breathed into the lungs, where they may irritate or damage the respiratory system. Higher amounts of particulates in the air therefore increase the risk of respiratory problems.

Particulates and global dimming

Particulates scatter or absorb sunlight as it passes through the atmosphere. This means less solar energy reaches the Earth’s surface. The reduction in sunlight reaching the surface is called global dimming.

Carbon monoxide as an atmospheric pollutant

Carbon monoxide, $$\ce{CO}$$, is a toxic gas pollutant. It is colourless and odourless, so people cannot easily notice it in the air. Exposure can therefore occur without an obvious warning.

Carbon monoxide interferes with the transport of oxygen in the blood. It binds strongly to haemoglobin, the substance in red blood cells that normally carries oxygen. When carbon monoxide occupies haemoglobin, less oxygen can be carried to body tissues.

As the amount of carbon monoxide in the air increases, it creates a serious health hazard because it can reduce the oxygen reaching tissues. Its lack of colour and smell makes the danger harder to detect.

Sulfur dioxide and nitrogen oxides as atmospheric pollutants

Sulfur dioxide and nitrogen oxides are gases that pollute the air. People can breathe them in, and they can also react in the atmosphere to make rain more acidic.

Effects on health

These gases can irritate the respiratory system, causing breathing problems and worsening conditions such as asthma. When their concentrations in the air increase, people may be exposed to more of the gases, increasing the risk of these effects.

Formation and effects of acid rain

Sulfur dioxide and nitrogen oxides react with oxygen and water in the atmosphere to form acids. These acids make precipitation, including rain, more acidic; this is called acid rain.

Acid rain can damage plants and make lakes and rivers more acidic, harming aquatic ecosystems. It can also react with building materials, gradually eroding buildings.