Latest research shows that air pollution affects women more than men.

Researchers at Pennsylvania State University studied two groups of mice with pneumonia. One group was exposed to ozone, an air pollutant. The other group breathed filtered air.

The exposure to ozone significantly decreased the likelihood of female mice surviving pneumonia as compared to males, reported science portal SCIENCE A GoGo.

The researchers also found that mice exposed to ozone died more often than mice that breathed filtered air.

At ground level, ozone is a dangerous air pollutant that can cause irritation in the respiratory system, triggering shortness of breath, chest pain when inhaling deeply and wheezing and coughing.

Ozone is formed when sunlight acts on hydrocarbon pollutants spewed out into the air by vehicles and such industrial processes as painting, oil refining and manufacture of chemicals.

Ozone is a major pollutant in American cities and more than 100 million people in the US live in areas with ozone levels higher than recommended air quality standards. India is also emerging as a hotspot for ozone pollution.

The latest study is the first to suggest that air pollutants have a significantly higher negative effect on females, compared to males. However, scientists have found in the past that there are differences in immune function between males and females.

"If we could extrapolate what we found to the human population, it would mean women with lung infections may be at higher risk for negative outcomes if they are exposed to high amounts of air pollution, and in particular, ozone," researcher Joanna Floros said.