In 2013, the annual mean nitrogen dioxide level in London was estimated as 58 μg /m3 but the save and "threshold limit value" is 40 μg /m3. In March 2015, Brussels took the United Kingdom into court for breaching emissions limits of nitrogen dioxide at its coal-fired Aberthaw power stations in Wales. The plant operated  under a permit allowing emissions of 1200 mg/Nm3, which is more than twice the 5 mg/Nm3 limit specified in the EUs large combustion plant directive. Prognosis
Generally, long-term prognosis is helpful to survival of initial exposure to nitrogen dioxide. Some cases of nitrogen dioxide poisoning resolves with no observable symptoms and patient may be determined by pulmonary function testing. If chronic exposure causes lung damage, it could take several days or months for the pulmonary function to improve. Meanwhile, permanent mild dysfunction may result from bronchiolitis obliterans and could manifest as abnormal flow at 50 to 70 percent of vital capacity. It may also manifest as mild hyperinflammation, airway obstruction and in that case, patient may be subject to steroid treatment to treat deconditioning. Complications from prolong exposure includes  bronchiolitis obliterans and other secondary infections such as pneumonia due to injuries on the mucous membrane from  pulmonary edema and inhibition of immune system by nitrogen dioxide. Nitrogen dioxide inhalation can result in short and long-term morbidity or death depending on the extent of exposure and inhaled concentration and the exposure time.
Serogroup A
A vaccine called MenAfriVac has been developed through a program called the Meningitis Vaccine Project and has the potential to prevent outbreaks of group A meningitis, which is common in sub-Saharan Africa. Serogroup B
Vaccines against serotype B meningococcal disease have proved difficult to produce, and require a different approach from vaccines against other serotypes. Whereas effective polysaccharide vaccines have been produced against types A, C, W-135, and Y, the capsular polysaccharide on the type B bacterium is too similar to human neural adhesion molecules to be a useful target.A number of "serogroup B" vaccines have been produced. Strictly speaking, these are not "serogroup B" vaccines, as they do not aim to produce antibodies to the group B antigen: it would be more accurate to describe them as serogroup independent vaccines, as they employ different antigenic components of the organism; indeed, some of the antigens are common to different Neisseria species.A vaccine for serogroup B was developed in Cuba in response to a large outbreak of meningitis B during the 1980s. This vaccine was based on artificially produced outer membrane vesicles of the bacterium. The VA-MENGOC-BC vaccine proved safe and effective in randomized double-blind studies, but it was granted a licence only for research purposes in the United States as political differences limited cooperation between the two countries.Due to a similarly high prevalence of B-serotype meningitis in Norway between 1974 and 1988, Norwegian health authorities developed a vaccine specifically designed for Norwegian children and young adolescents.