Cystic fibrosis is a recessive genetic disorder. It means that the trait is caused due to the presence of a recessive allele. The recessive alleles are expressed only in homozygous recessive genotypes. Individuals that express the disorder cystic fibrosis should have two copies of a recessive allele of the gene, that is, the genotype should be homozygous recessive.
If "C" allele is the normal healthy allele and "c" allele is cystic fibrosis allele, the genotype of the affected individual would be "cc".
Measure CO2 Levels from around the town to see if the ratio of Oxygen to CO2 is irregular. It's also important to take in factor how much CO2 intake the plantation around them is so you can see what the entire amount is.