3 public questions tagged with this topic.
Lichens do not grow in polluted areas. Therefore, their absence from a locality can indicate the presence of environmental pollution.
Ref: NCERT Class 11 Biology Chapter 2: Biological Classification Viruses Viroids Prions and Lichens
India's Central Pollution Control Board coordinates and specifies National Ambient Air Quality Standards under the national pollution-control framework, working with state boards on monitoring and implementation. The standards prescribe limits for pollutants such as particulate matter, sulfur dioxide, nitrogen dioxide, ozone, carbon monoxide, lead, ammonia, benzene, and selected toxic substances. WHO issues health-based guidelines internationally, while UNEP is not India's statutory standard-setting authority. The distinction is ecologically important because emission control must target either the directly released precursor or the product formed after atmospheric transport and reaction. Exposure depends on concentration, duration, ventilation, weather, and individual susceptibility, so a pollutant's presence alone does not fully predict biological harm. Atmospheric inversions can trap contaminants near the surface, while wind, turbulence, precipitation, and chemical transformation determine their eventual distribution and removal. At organismal level, respiratory surfaces are especially exposed because large volumes of air contact thin, moist epithelia designed for rapid gas exchange.
Ref: Campbell Biology, Urry et al., 12th Ed., Unit 8 Ecology
Methane is an important greenhouse gas and a precursor in atmospheric chemistry, but it is not one of the conventional criteria air pollutants regulated through ambient concentration standards. Lead, carbon monoxide, and ground-level ozone are criteria pollutants because widespread exposure and documented health or environmental effects justify routine monitoring and legally defined limits. Sound classification links the source, atmospheric fate, exposure route, and mechanism of toxicity rather than relying only on the pollutant's name. Effective management combines cleaner fuels, emission standards, monitoring, urban planning, and protection of populations with high exposure or physiological vulnerability. The distinction is ecologically important because emission control must target either the directly released precursor or the product formed after atmospheric transport and reaction. Exposure depends on concentration, duration, ventilation, weather, and individual susceptibility, so a pollutant's presence alone does not fully predict biological harm. Atmospheric inversions can trap contaminants near the surface, while wind, turbulence, precipitation, and chemical transformation determine their eventual distribution and removal.
Ref: Campbell Biology, Urry et al., 12th Ed., Unit 8 Ecology
