LAHORE: Agriculture experts on Wednesday said that critical mix of smog and fog could cause decline in vegetables, fruits and crops yields in the province.

Talking to APP, an expert said that burning of coal and other fossil fuels give rise to various chemical pollutants such as sulphur dioxide, nitrogen oxides nitrate, etc. International Union for Conservation of Nature (IUCN) country representative, Mahmood Akhtar Cheema said that gaseous emissions are the main elements that form smog. The gaseous emissions when acted upon by the sun's ultraviolet light, particulate matter and volatile organic compounds present in the air usher in smog. Dense urban areas suffer more from smog because of huge number of vehicles, industries and combustion of different types of fuel, he said, adding that smog has serious negative impacts on people, plants and animals, he said. Cheema said that Ozone and peroxyacetyl nitrate (PAN) get produced during the mixing of pollution/smog and fog, and this reaction was harmful to vegetables, fruits, plants and crops depending on concentration and duration of exposure.

To a question, he said that Ozone, peroxyacetyl nitrate and hydrogen sulphide got mixed in the smog which caused upto 90 percent of the air pollution.These gases kept constantly affecting the vegetation during the last one decade.He said wheat plant, orange gardens, vegetables and grass/fodder for animals could be affected in the coming days. Dr Ijaz Bhatti,a noted scientist said most of the polluting gases enter leaves through stomata,following the same pathway as CO2. NOx dissolves in cells and gives rise to nitrite ions (NO2), which are toxic at high concentrations) and nitrate ions (NO3) enter the nitrogen metabolism of the plant as if they were absorbed by the roots. In some cases, exposure to pollutants in air or smog, particularly SO2, causes stomata of leaves to close.This closing protects the leaf against further entry of the pollutants, but it also stops photosynthesis, a process which creates nutrition for the whole plant. Tomato,potato,string beans,snap beans,pinto beans,tobacco, soybeans, cantaloupe,beets,sunflower,carrots,sweet corn,gourds,green peas, turnips, grapes, peaches, and strawberries were some of the crops more susceptible to smog and air pollution, he said. Lahore University of Management Sciences research scholar Syed Shehzad-ul- Hassan called for greater reliance on renewable energy sources,and said that efficient use of energy ,and at the same time conserving energy could lead to lesser gaseous emissions that often result in the formation of smog.