Tag: air and air pollution

Lead's four stable isotopes each have 82 protons, a magic number in the nuclear shell model of atomic nuclei. The isotope lead-208 also has 126 neutrons, another magic number, and is hence double magic, a property that grants it enhanced stability: lead-208 is the heaviest known stable nuclide.

Almost all organ systems are affected by hydrogen sulfide, but the most susceptible are those with exposed mucous membranes (e.g., eyes,  noise and throat) and those with high oxygen demands (e.g., lungs, brain).

  At higher concentrations, hydrogen sulfide rapidly deadens the sense of smell which means the ability to sense the smell of anything will be no more at such high temperature.  For most people, this occurs at approximately $150ppm$. The gas has a characteristic rotten egg odour at low concentrations. About half of the population can smell it at concentrations as low as 8 parts per billion ($ppb$) in the air.

Hydrogen sulfide is the chemical compound with the formula $H _2S$. It is a colorless gas with the characteristic foul odor of rotten eggs; it is heavier than air, very poisonous, corrosive, flammable, and explosive.

$2H _2S+3O _2\longrightarrow \underbrace {2SO _2} _{sulphur\quad dioxide}+\underbrace {2H _2O} _{water}$

Exposure to $H _2S$ causes eye irritation thereby causes tearing of eyes. 

Because of its high reactivity toward glass and moderate reactivity toward many metals, hydrofluoric acid is usually stored in plastic containers (although PTFE is slightly permeable to it).

For hydrogen sulfide, it is allowable for workers to be exposed to concentrations of 10 parts per million, averaged over an eight-hour work shift, with the exposure not exceeding 15 parts per million. 
1000ppm and 2000ppm have high probability of death and lose consciousness.

Lead is a neurotoxin that accumulates both in soft tissues and the bones, damaging the nervous system and causing brain disorders.